Does anyone know of a tool that enables individuals to work out their personal carbon footprint? I'm just starting out as an official 'Carbon Champion' within my NHS organisation, and I'm trying to find a fun way of engaging people on the issue of carbon. I thought inviting people to use a fairly simple calculator to work out their personal carbon footprint in CO2 equivalents might work, but I can't find anything on the web. The Carbon Trust has one for whole organisations, but nothing for individual use.

A calculator that has been widely used and validatated to facilitate comparisons between individuals across different orgaisnations would be the ideal.

Thanks. Iain